Building the circular economy into construction

Increased circular economy thinking in construction is vital if we are to tackle the climate crisis, prevent biodiversity loss and address crucial social needs. Here, we examine the current state-of-play and focus on the key areas where meaningful change is not only possible, but critical.

The linear economy is the current ‘traditional’ model, based on a ‘take-make-consume-waste’ approach: Raw materials are transformed into a product and is wasted at its end of life – often twinned with the process of downcycling which produces materials of a lower quality and functionality than the original material. While this method does keep the materials in use and out of landfill, upcycling reuses waste in order to form a new product of equal or higher value.

In a circular economy – a key driver in the societal green transition –  manufacturers design products to be reusable and the end of the building’s life. To catalyse a holistic approach, circular economy should be viewed as a business strategy and not just a single aspect or bolt-on under the sustainability umbrella. The UKGBC Circular Economy Report (2019) also highlights the business opportunities that a circular economy can bring, which include the generation of a reliable, lower-risk cash flow, creation of long lasting client relationships and the de-risking of project pipelines.

Integration of reusable materials as part of a move to circular economy in construction (and wider infrastructure) introduces the concept of urban mining and material passports which allows the building to offer onward value during the end-of-life and deconstruction period. Material passports also act as a database for new developments to encourage material reuse and in turn reduce their environmental impact. These passports cover everything from the foundations of a building to the front façade, window frames and inner walls to the roof structure. The process of logging suitable materials for reuse will therefore facilitate wider-spread urban mining: treating a city like a mine of rich resources wherein valuable materials are acknowledged to exist and can be extracted.

It is true that industry practice is currently behind in such quantification, logging policies, and even expectation when it comes to a circular economy in construction. However, the underlying appetite is there and we are seeing Owners become increasingly motivated to incorporate circular principles into their developments.

Project Build scope – what are we working with?

First, the scope of the development should be assessed as this will determine the correct methodology for the circular approach. Often office developments are built to a Cat A scope to ensure spaces are more easily let and can be fit out to Cat B a lot faster. This can increase the amount of waste produced where the incoming tenants remove the newly installed Cat A elements.

Constructing a development to Shell & Core scope – as in our project at Bloom Clerkenwell – would be the most favourable as this would eliminate the requirements for finishes and provide capped services to allow for more flexibility with the incoming tenant.

Spaces that have already reached a Cat B fit out and have seen years of occupation should be subject to review by the next tenant to determine whether the space can be retained and reused with minor upgrades where required.

Debate: recycled vs recyclable

There has been a strong push to include materials with high recycled contents within new developments. A series of questions should be posed with regards to the use of recycled materials and whether recyclability is more important:

1. An assessment of durability and quality – Will this material stand the test of time?
2. Cost Benefit – Is it more cost effective to recycle the material and remanufacture?
3. Reusability – Will this product have the ability to be upcycled or downcycled?
4. Recyclability – Can this material be recycled at its end of life

In short, every project should endeavour to set out a Material Hierarchy of new materials entering the building – and establish the most suitable end-of-life use for each element.

Pre-demo and pre-refurb audits

Pre-demolition audits serve as a way to identify the construction waste materials that will come out of the demolition and decide how to manage this, and minimise the environmental impact by diverting waste away from landfill.

Typically, these audits are required as part of the BREEAM process – and as shown below are being strongly recommended by such as the London Plan to support circular economy statements as part of the planning stage of redevelopment. However, to ensure pre-demolition audits provide tangible waste solutions their scope needs to be enhanced beyond BREEAM.

Pre-demolition audits need to be seen as strategic guides – and include not just the generic waste groups but details on the type of material and the quality for either direct reuse or down- or upcycling within the development. The demolition contractor must, in alignment, expand their scope and provide clear waste options.

To facilitate this process the Architect should have direct input during the site visits, material identification and quality assessments. Following this, areas of direct reuse can be identified for the proposed developments where direct retention is not possible. These activities must be undertaken at the earliest stages to ensure that the qualifying materials are incorporated into the development for circular design.

Furthermore, this will steer us in a direction where pre-demolition audits become moot as Disassembly Guides, Urban Mining Portfolios and Material Passports encompass new elements installed in developments.

Changing mindsets

An important step to changing the industry is changing the overall mindset of all parties involved from the developers to the incoming tenants. Presently there is a desire for new materials, new developments, and new equipment. Where items are built in obsolescence as a society we expect new above all else. It is time to change this mindset and pride ourselves on reuse – and low carbon retrofits in particular – to increase life expectancy of buildings and materials.

Owners of course develop buildings with the intention that these will remain for generations without demolition, full stop. However we should be building any new structures with the expectation that these can be disassembled and mined for materials in future. An adaptable building is a durable one – as can be seen when evolving office space into academic venues.

Putting in the work – the need for collaborative effort

Creating circular solutions requires a collaborative effort between all parties, with roles and responsibilities defined at the start of each project.

The Client should be responsible for setting out policies for circular opportunities whether these be concise or broad in nature. This is to steer not only the individual developments but the developer’s portfolio towards the future of urban mining in the UK.

The Demolition Contractor is then responsible for formulating a clear and concise audit of the materials in the development. They should work with the design team to identify direct re use in the development and externally.

Ultimately, the challenges and solutions identified above will steer us into a more circular future across the construction industry. Countries in Scandinavia and the Netherlands have already embraced circularity – many are well into the journey towards circular city transformation – and we can learn a lot from their practices in future developments to come. Engagement with each other is vital if we are to share the knowledge and skill sets that will unlock a circular transformation on a global scale.

Circular economy trend #1:Growth thinking

Turning waste into an asset

Dredging. The word conjures up the disposal of something worthless or unwanted, like a waste product. But in a circular economy, not only does it play a role – it can become valuable in its own right.

“Our water-passing tile is made from dredged sediments,” says Wies van Lieshout, co-founder of the Dutch start-up Waterweg. “It’s a circular, climate-adaptive product. The tiles are made from river sediment waste and provide a solution for flooding in cities. Dredging is the tool we use to make an impact.”

The summer of 2021 saw flooding across Europe, and together with climate change is not a problem that is likely to go away. Recycling alone no longer suffices for achieving an economy that is truly circular.

During budgeting and financial planning, we really have to go beyond creating spaces for production and employment – it’s a complete mind shift. “We have to think about the future of spaces and cities. It’s not only about closing loops.

Kathleen Van de Werf Business Development Manager at BUUR (part of Sweco)

Although the world’s cities currently occupy less than 4% of Earth’s surface, they are home to 55% of the global population. They consume more than 75% of our natural resources, produce more than 50% of all global waste, and emit 60-80% of global greenhouse gases. These are all symptoms of a take–make–dispose linear economic model. And cities continue to grow: by 2050, two-thirds of us will live in cities.

Circular economy trend #2: Circular thinking

Meeting the European circular promise

In March 2020, the European Commission adopted the Circular Economy Action Plan as a part of the European Green Deal with the goal to achieve a carbon-neutral, sustainable, non-toxic and fully circular economy by 2050.

As a part of the plan, 70% of all construction waste must be recycled from 2020 onwards, accelerating the construction industry’s switch from a linear to a circular strategy.

Many European countries have presented an agenda of their own. In 2016, Finland became the first country in the world to prepare a strategic national roadmap for a circular economy by 2035. Denmark followed, launching its circular economy strategy in 2018 for full implementation by 2022. The U.K. is another example, with generally the same plan as the European Commission’s.

In 2021, an international alliance called the Global Alliance on Circular Economy and Resource Efficiency (GACERE) was formed to drive the global circular conversion. A growing number of cities have also prepared circular economy plans, roadmaps or declarations, several of which pre-date the 2020 Circular Economy Action Plan. Amsterdam, London, Glasgow, Copenhagen – these are just some of the cities recognising the need for cities with definitive plans to increase circularity within their own urban resource systems.

These plans re-think cities as circular resource systems, and identify action plans to turn this thinking into reality.

Industry needs to move faster – and smarter. In our full Circular Economy Trends Report, we place the spotlight on a host of new, innovative ways to achieve a circular construction sector, through reuse, repurposing, recycling and closing loops.

We also highlight the need for a circular systems approach, which considers not just individual projects but embraces collective initiatives with all relevant stakeholders. In our view, achieving the highest levels of circularity demands a complete mindset shift.